In agricultural biotechnology, plants can be modified according to one's needs. One way to accomplish this is by using modern genetic engineering techniques. For example, by introducing a gene of interest into a plant, the plant can be specifically modified to express a desirable phenotypic trait. For this, plants are transformed most commonly with a heterologous gene comprising a promoter region, a coding region and a termination region. When genetically engineering a heterologous gene for expression in plants, the selection of a promoter is often a factor. While it can be desirable to express certain genes constitutively, i.e. throughout the plant at all times and in most tissues and organs, other genes are more desirably expressed only in response to particular stimuli or confined to specific cells or tissues.
It has been shown that certain promoters are able to direct RNA synthesis at a higher rate than others. These are called “strong promoters”. Certain other promoters have been shown to direct RNA synthesis at higher levels only in particular types of cells or tissues and are often referred to as “tissue specific promoters”, or “tissue-preferred promoters”, if the promoters direct RNA synthesis preferentially in certain tissues (RNA synthesis can occur in other tissues at reduced levels). Since patterns of expression of a nucleotide sequence of interest introduced into a plant, plant tissue or plant cell are controlled using promoters, there is an ongoing interest in the isolation of novel promoters that are capable of controlling the expression of a nucleotide sequence of interest at certain levels in specific tissue types or at specific plant developmental stages.
Furthermore, this document incorporates herein by reference US Patent Application Publication No: 2007/006344, Ser. No. 11/109,594 in its entirety.